What that tells us is that, roughly speaking, a randomly selected password has a better than 80% chance of featuring in the list. The list has a few hundred million entries, compared with a few hundred billion options for random 8 letter passwords. So, roughly speaking our hacker trying 8 letter passwords would have a 0.1% chance without the list in the time they could get an 80% chance with the list. Obviously they'd want to use it. And again, you might as well avoid it. After all, you still have hundreds of billions of options to choose from, and you can get thousands of billions by just going to nine letters!